This invention relates to a coffee roaster, and more particularly, to a control device for controlling the roasting temperature of a coffee roaster.
There are two common methods of roasting coffee, a hot blast method and a heat radiation method. When using either method, the coffee beans should be roasted within a very short time period to produce high quality coffee beans. Therefore, coffee roasters use heater elements with large calorific values for quickly roasting the coffee beans. However, since coffee roasters are not provided with a device for controlling the calorific value of the heater element, the temperature in the roaster may abnormally increase and the outer skin of the coffee bean may burn.
Some roasters are equipped with devices for more uniformly roasting the coffee beans, for example, a stirring element or a blower device to control the flow of air into the roaster. Thus, heat is more uniformly distributed to each coffee bean due to the stirring of the beans and air circulation caused by the blower element. However, the calorific value of the heater element proportionally changes in accordance with changes in the power source voltage so that the amount of heat absorbed by each coffee bean within a predetermined time period may change. As a result of variations in the heating of the beans, the roasting condition changes thereby making it difficult to control the degree to which each bean is roasted.